The present invention relates to a shoulder endoprosthesis for fractures of the upper end of the humerus.
It is known that among the various kinds of fracture of the upper end of the humerus four-part fractures are the most severe and often require surgical treatment when the fragments of the fracture are mutually dislocated.
In a four-part fracture the muscles play a key role in the pathophysiology of this type of fracture, since they pull in different directions on each fragment of the fracture. As shown in FIG. 1, the diaphysis 1, the fragments of the inferior tuberosity 2, the upper tuberosity 3 and the humeral head 4 are separated one another and the fracture is not simple. Conservative treatment by surgical reduction is not satisfactory and very often causes pseudarthrosis or necrosis of the humeral head.
Accordingly, in these cases the only possible treatment that allows to recover complete mobility and eliminate pain is joint replacement.
Most surgical procedures that use shoulder joint prostheses are the consequence of fractures.
Currently known shoulder prostheses are mainly cemented and have holes in the proximal-lateral part in order to allow fixation of the tuberosities. However, the location of said holes makes it difficult to achieve stable fixation of the tuberosities; accordingly, fragment consolidation is often not achieved and patients complain of continuous pain and unsatisfactory mobility of the joint.
With most of the currently known shoulder prostheses, once the cement as set it is not possible to correct retroversion and therefore position the rosthesis appropriately.
The aim of the present invention is to provide a shoulder endoprosthesis which can be applied in the case of multiple fractures without requiring bone cement.
Within the scope of this aim, an object of the present invention is to provide a shoulder endoprosthesis which allows to restore humeral length and correct retroversion.
Another object of the present invention is to provide a shoulder endoprosthesis which allows to fix the tuberosities to the diaphysis as well as to the prosthesis.
Another object of the present invention is to provide a shoulder endoprosthesis which allows to reposition the tuberosities with the correct tension and in the correct seat.
Another object of the present invention is to provide a shoulder endoprosthesis which is highly reliable, relatively easy to manufacture and at competitive costs.
This aim and these and other objects which will become better apparent hereinafter are achieved by a shoulder endoprosthesis for fractures of the upper end of the humerus, characterized in that it comprises a humeral stem, which is suitable to be accommodated in an intramedullary canal of the humerus and is provided with multiple longitudinal ribs, and a humeral proximal part, which is suitable to couple to one end of said stem, is provided with multiple lateral fins and has, at an upper end, a portion for engagement with a humeral head which is suitable to reconstruct the head of the humerus of the patient.